Abstract
A survey for endemic goiter was carried out on Iban natives (Sea Dayak) in four districts along the Rajang River in Sarawak, Borneo Island.
Among 608 subjects (271 males and 337 females) examined, 134 subjects (22 males and 112 females) were found to be goitrous, the prevalence of goiter being 8.1 for male and 33.2% for female. None were clinically hypo-or hyperthyroid, no cretinism was detected.
Twenty-four hr. thyroidal 131I-uptake was 54.3±13.1 %(mean±S. D.) in goitrous subjects while 47.1±10.2% in non-goitrous (no statistical significance). Urinary excretion of iodine was 45±27μg per day in goitrous group and 49±25μg in nongoitrous group (no significance). Iodine content of drinking water was extremely low in all four districts, the lowest one being obtained from region in which the prevalence of goiter is highest. Thyroid parameters such as PBI, T3 resin sponge uptake and cholesterol were all within normal limits. Anti-thyroid antibodies were not demonstrated in sera from either goitrous or nongoitrous subjects. KSCN discharge test was positive in two cases in a single family, among 33 cases studied.
Experimental feeding of cassava on our expedition members for two weeks did not show any change in thyroid parameters including KSCN discharge test.
It is thought that iodine deficiency is probably a major causative factor of endemic goiter in Sarawak, Borneo Island. Other factors such as organification defect or defective thyroxine binding proteins might have some role in individual cases.
